Thread-cutting mechanism for sewing-machines.



No. 702,832. Patented lune l7, I902.

R. W. THOMSON.

THREAD CUTTING MEGHANiSM FOR SEWING MACHINES.

(Application filed June 7, 1897.)

6 Sheets-Sheet I,

(No Model.)

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No. 702,832. Patented June l7, I902.

R. W. THOMSON.

THREAD CUTTING MECHANISM FOR SEWING MACHINES.

Application filed June 7, 1897.) (No Model.) 6 Sheets-Sheet 2.

No. 702,832 Patented lune-l7, I90 R. W. THOMSON. THREAD CUTTING MECHANISM FOR SEWING MACHINES.

(Application filed June 7, 1897.)

6 Shests Sheet 3.

(No Model.)

Woses:

m: Ncnms vz'rzns co. woromwo, WASHINGTON, n. u

No. 702,832. I Patented lune l7, I902.

' R. W. THOMSON.

THREAD CUT'HNG MECHANISM FOR SEWING MACHINES. (Application filed 3mm 7, 1397 6 Sheets$heet 4.

("0 Model.)

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No. 702,832. Patented June l7, I902.

R. W. THOMSON. THREAD CUTTING MECHANISM FOR SEWING MACHINES.

(Application filed Jute 7, 1897.) (No Modei.) 6 Sheets-8heet 5.

TQH'E noams vrrzns 0a., PHOTO-LITHO WASNINGTUM'D. c.

No. 702,832. Patented June I7 I902.

n. w. THOMSON. THREAD CUTTING MECHANISM FOR SEWING MACHINES.

(Application filed June 7, 1887.)

(No Model.) 6 Sheets-Sheet 6.

FIG/6 M W Iw c y I I Inventor: llo

. m5 NpERvs wzrms cc. PHOTO-LUNG, wAsumorom u c UNITED STATES PATENT OFFICE.

ROBERT "W. THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THE PHILA- DELPHIA EARRING MACHINE COMPANY, OF CAMDEN, NEW JERSEY, A CORPORATION OF NFJV JERSEY.

THREAD-CUTTING MECHANISM FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 702,832, dated June 17, 1902. Application filed June '7, 1897. Serial No. (139,742. (N model-J T19 all 107w? it y OOYWWW away and part of the machinery removed, so

Be it known that 1, ROBERT W. THOMSON, as to illustrate the parts beneath. Fig. 3 is a subject of the Queen of Great Britain and a side view of the machine looking in the di- Ireland, and a resident of Lynn, Massachurection of the arrow m, Fig. 2. Fig. 4 is a 5 setts, have invented certain Improvements side View of the machine looking in the direc- 55 in Sewing-Machines, of which the following tion of the arrow 3 Fig. 2. Fig. 5 is an end is a specification. view of the machine looking in the direction My invention relates to that class of maof the arrow 10, Fig. 2. Fig. 6is an inverted chines such as are employed for forming a plan or bottom view of the machine. Fig. 7

1o strengtheningor staying bar at the end of is a sectional View of part of the automatic 6o abuttonhole orforforminga tack or group stop mechanism of the machine. Fig. 8 is a of stitches where two edges of the material to perspective View of part of the mechanism be sewed meet or overlap, as in shoe-uppers employed for nipping the needle -thread. and the like, such machines being usually Fig. 9 is a sectional view illustrating the IS constructed so as to form the desired group means employed for preventing back move- 65 of stitches and then stop automatically in ment of the driving-shaft when the machine order to permit readjustment of the material is stopped. Figs. 10, 11, and 12 are inverted preparatorytotheformationof another group plan views illustrating the thread-cutting of stitches in a new location, and each group mechanism in different positions and showof stitches usually comprises two or more ing the vibrating hook and bobbin in dotted 70 long stitches extending in one direction and lines. Figs. 13, 14C, and 15 are exaggerated a series of short stitches extending in the opsectional views showing the thread-cutting posite direction and formed over said long knives respectively in the positions of Figs. stitches, the latter thus serving as a core for 10, 11, and 12; and Figs. 16 to 19, inclusive,

the bar or tack and the short stitches being are views illustrating modified forms of 75 distributed uniformly from end to end of this thread-cutting devices. core or being grouped in any manner desired. The base-plate of the machine is represent- My presentinvention comprises certain imed at 1 and is mounted, by means of hinges provementsin machines for whichI obtained 2, upon supporting-frames 3, which are in- Letters Patent No. $5,891, dated August tended to be properly secured to a suitable 8o 27, 1895, the objects of my said improvework table or bench, so that the base-plate 1 ments being to prevent backlash or reversal and all of the machinery mounted thereupon of movement of the machine when it has can be thrown backward in order to permit stopped after completing a bar or tack, to ready access to the mechanism which is begovern the movement of the cutting-knife, to neath the base-plate. 85 effect the automatic release of the work from Secured to the base-plate 1 and extending the work-holding clamp whenit becomes necupwardly therefrom is a standard 4, from essary to shift the work from one position to which projects the hollow arm 5, which has another, to prevent the release of the cut end suitable bearings for the main driving-shaft of the needle-thread from the needle, and to 6, the latter being provided at the front end 0 effect the automatic cutting off of both the with the ordinary mechanism for imparting needle-thread and the under thread when a a Vertical reciprocation to the needle-bar 7 group of stitches is completed. These oband for operating the take-up arm 8, while jects I attain in the manner hereinafter set the rear end of ,the shaft projects beyond the forth, reference being had to the accompastandard and is provided with a fast pulley 95 nying drawings, in which 9 and a loose pulley 10 for receiving a driv- Figure 1 is an exaggerated view of agroup ing-belt. The shaft 6 is provided with the ofstitchessuch asconstitute an ordinary butusual worm, (not shown in the drawings,) tonhole-bar. Fig. 2 is a plan or top view of which engages with the teeth of aworm-wheel the machine with part of the arm broken 11, secured to the shaft of a cam-disk 12, I00

'chine.

which has cams for operating the clamp-bar, whereby the work is carried backward and forward beneath the needle, it being understood that the Work is rigidly held in the forward end of this clamp-bar, so as to partake of the movements of the same and so that it cannotv be accidentally displaced from its proper position therein.

The disk 12 has in its outer face a camgroove 13, which acts upon an antifrictionroller 14, carried by the upper end of an arm 15, which is secured to a rock-shaft 16, mounted in a suitable bearing 17, secured to the base-plate of the machine, said rock-shaft 16 having an arm 18, which carries an adjustable block 19, engaging with a vertical pin 20, projecting upwardly from the clamp-bar 21, so that asthe disk 12 is'rotated said clam pbar will be caused to move back and forth in the direction of the length of the machine, the extent of movement being governed by adjustment of the block 19 nearer to or farther from the rock-shaft 16.

On the inner side of the disk 12 is formed a cam-groove 22, which engages with an antifriction-roller on the upper arm of a lever 23, the latter being mounted so as to swing freely on the rock-shaft 16, and having a lower arm projecting down through an opening in the bed-plate of the machine and provided below said bed-plate with a horizontally-swinging arm 24, Fig. 6, to which arm is hung the forked rear endof a rod 25, the forked forward end of said rod being hung to a block 26, which can be adjusted laterally in a slot 27, formed in one arm of a bell-crank lever 28, which is pivoted to a stud on the under side of the bed-plate and has another slotted arm engaging with a block 29, projecting downwardly from the clamp-bar 21 through an opening in the base-plate of the ma- The grooved cam 22 therefore causes movement of the clampbar in a direction crosswise of the length of the machine, and said cam 22 is so formed as to provide for any desired disposition of the short crossstitchesthat is to say, they may be distributed uniformly from end to end of the bar, as shown in Fig. 1, may be grouped in the center of the bar, or may be divided, a portion of the stitches being at one end of the bar and the remaining stitches at the other end of the bar, the length of the stitches being regulated by adjusting the block 26 in the slot 27 of the lever'28, so as to vary the throw of that arm of said lever which engages with the stud 29 on the under side of the clamp-bar.

During the operation of the machine the belt-shifter 33 is held in the position shown in Fig. 3 (so as to direct the driving-belt onto the fast pulley 9) by means of a retaining-lever 34, which is normally held in engagement with the arm 35 of the belt-shifter by means of a spring 36. Just before the group of stitches is completed, however, a cam 37 on the inner side of the disk 12 trips the lever 34, and thereby permits the shifter-arm to move outward under the influence of a spring 38, Fig. 3, so as to carry the driving-belt from the fast pulley 9 onto the loose pulley 10, so that there will be no further application of power to the machine. At the same time a bolt 39, carried by the shifter-arm 35 and projected by means of a spring 40, is brought into the path of a cam 41 on the driving-shaft of the machine, and the momentum of the parts causes the shaft to revolve in the direction of the arrow, Fig. 7, until the shoulder 42 of said cam comes into contact with the upper end of the bolt 39. A slight lateral movement is thus transmitted to the bolt 39 and shifter-arm 35, owing to the fact that said shifter-arm is hung to a block 43, pivoted by a stud 44 to the standard 4 of the machine. This lateral movement of the arm 35 is transmitted to a sliding bolt 45, adapted to a suitable bearing in a bracket 46, forming part of the fixed frame of the machine, said bolt being constantly kept in contact with the arm 35 by the action of a spring 46, hearing against a collar 47 on the bolt and adjustable in strength by screwing up or unscrewinga nut or sleeve 48, adapted to a threaded opening in the bracket 46. (See Fig.7.) The bolt 45 projects through the nut 48, and said projecting end of the bolt acts upon a setscrew 49, carried by the upper end of a lever 50,which is secured to a rock-shaft 5l,n1ounted in a bracket on the base-plate of the machine.

The lower end of the lever 50 is perforated for the reception of a rod 52, which has a collar 53, on which said lower end of the lever acts, and on said rod 52 is an adjustable collar 54, adapted to act upon one arm of a bellcrank lever 55, which is hung to a bracket 56 on the base-plate, the upper arm of said bell-crank lever being connected by a link 57 to the rear end of a lever 58, hung to a bracket 59, also on the base-plate of the machine. The front end of said lever 58 is bent laterally, so as to project under a pair of hooked pins 60, carried by the elastic upper clamp-plates 61, which serve to confine the material toa plate 62, secured to the forward end of the clamp-bar 21, said plate 62 being properly recessed at the front edge, so as to permit of the desired play of the clampbar in respect to the needle. When, therefore, the machine is stopped by contact of the shoulder 42 of the cam 41 with the upper end of the bolt 39, there will be a simultaneous lifting of the upper or spring jaw of the clamp, so as to release the work and permit it to be moved forward in order to bring a fresh port-ion of the work into position beneath the needle for the formation of the next group of stitches. In order to retain the clampjawin this elevated position until the machine is again ready to start, the lower arm of the bell-crank lever 55 when pushed outward by the action of the collar 54 on the rod 52 is caught and held in this position by a catchplate 63,which is adj ustably mounted upon an arm 64, hung to the base-plate of the machine and acted upon by a spring-bolt 65, which tends to press the arm 64 backward, so as to cause the catch-plate 63 to have anormal tendency to engage with the lever 55. It is therefore necessary to impart a forward movement to the arm 64 in order to release the catchplate 63 from engagement with the lever 55, and thus permit the descent of the clamp before starting the machine, and this is effected in the following manner: Mounted in suitable hangers 66 at the back of the machine is a rock-shaft 67, which has three arms 68, 69, and 70. The arm 68 is intended to be connected to a treadle or other suitable start-.

ing device, whereby downward pull upon said arm can be caused. The arm 69 has a beveled front end acting upon the outer end of the arm 64, and the arm 70 is connected bya chain 71 to a lever 72, hung to a bracket on the fixed frame and acting upon the arm 35 of the belt-shifter.

There is a slight amount of slack in the chain 71. Hence when the outer end of the arm 68 is drawn downward the first effect of the operation will be to lift the arm 69, and thereby cause its beveled end to push forward the arm 64, and thus move the catchplate 63 out of engagement with the lever 55 in order to permit the clamp to close upon the work, continued movement of the arm 68 causing like movement of the arm 70 and tightening the chain between the same and the lever 72, and the latter is thus caused to act upon the arm 35 of the belt-shifter, so as to move the upper end of the latter forward and carry the belt onto the fast pulley 9, the arm being retained in this position by engagement with the catch-lever 34 until said catch-lever is again tripped by the cam 37 on the disk 12 after a new group of stitches has been completed.

The usual crank on the driving-shaft 6 is connected by a rod 74 to an arm 75 on a rockshaft 76 beneath the base-plate 1 of the machine, and said rock-shaft has an arm 77 with slotted plate engaging a pin on an arm 78 of a shaft 79, which is mounted in bearings beneath the base-plate 1 and has at its forward end a hook-driver 80, to which vibrating movement is thus imparted, the vibrating hook operating in conjunction with the needle and with any ordinary form of bobbin 73, so as to form a double-thread lock-stitch.

Hung to the under side of a throat-plate 81, which is adapted to a recess in the front end of the base-plate 1, is a lever 82, which carries two cutters S3 and 84, the cutter 83 being intended to cut the loop of needlethread at the completion of a group of stitches and the cutter 84 being intended to cut the shuttle-thread, the operation of these parts being more fully referred to hereinafter.

The lever 82 is connected by a link 85 to one arm of a lever 86, which is hung to a stud 87 on the under side of the base-plate 1, the rear end of said lever 86 having a projecting pin 88, which is connected by alink 89 to the lower end of an arm 90, secured to the rockshaft 51, said rock-shaft also having another arm 91 with projecting stud, adapted to be acted upon by a cam 92, adjustably secured upon the outer face of the cam-disk 12.

Projecting inwardly from the arm 90 is a stud 93, and to the latter is hung a lever 94, the depending arm of said lever being such that when the rock-shaft 51 and its arms 90 and 91 are in their normal position said depending arm of the lever 94 will occupy a position in front of a stop-lug 95 on the baseplate 1, the lever being held in this position by means of a spring 96. When, therefore, the arm 91 is acted upon by the cam 92 and said arm is swung outward, the arm 90 will swing inward until the lever 94 comes into contact with the stop-lu g 95, thereby preventing undue forward movement of the knifelever 82, which receives its movement from the arm 90, so that the knives are prevented from moving beyond a certain predetermined position. 011 the cam-disk 12, however, is a lug 97, and at the proper time in the operation of the machine thislug strikes the upper or short arm of the lever 94 and trips the same, so as to permit further movement of the rock-shaft 51 and its arms 90 and 91. A two-stage movement is thus imparted to the lever 82, which carries the thread-cutting knives, the first stage of the movement being due to the action of the cam 92, and any eX- cess of movement due to momentum of the parts being prevented by action of the stoplever 94. The second stage of themovement is a quick one, first forwardly from this position of rest and then backwardly to the normal or fully-retracted position. This movement is effected by theaction of the stopping devices of the machine, the lateral swinging movement of the stop-arm 35 due to contact of the shoulder of the cam 41 with the bolt 39 being transmitted to the sliding bolt 45 and by the latter to the lever 50, rock-shaft 51, andparts operated by the latter.

In order to prevent any back movement of the machine due to recoil when the shoulder 42 of the cam 41 strikes the bolt 39, the driving-shaft 6 is provided with a catch-lug 98, with which is adapted to engage a pawl 99, hung to a bracket on the frame of the machine, the outward movement of the pawl being restricted by a pin 99, projecting from the bracket to which the pawl is hung. The catch-lug 98 is so disposed upon the shaft 6 with reference to the cam 41 that when the shoulder 42 of said cam strikes the bolt 39 the abrupt end of the catch-lug will have just passed beyond the end of the pawl 99. Hence the latter will drop behind said abrupt end of the catch-lug and will prevent any back movement of the shaft.

Mounted upon the needle-bar of the machine, just above the needle, is a threadclamping plate 100, slotted, as shown at 101 in Fig. 8, so that the needle-thread can be IIO &

readily passed behind the same before being passed through the eye of the needle, and on the needle-bar is mounted a lever 102, having a pin 103, adapted to bear upon the outer face of the clamping-plate 100, the upper end of this lever being acted upon by the forward end of a rod 104, which is normally pushed rearward by means of a spring 105, adapted at one end to a socket in the head of the machine and bearing at the other end against an adjustable collar 106 on the rod 104. The rear portion of the rod has an adjustable collar 107, which is acted upon by a spring 108, interposed between said collar and the lower end of an arm 109, through which the rod 104 passes, said arm 109 projecting from a hub 110, which is hung upon a stud 111, projecting from the arm 5, said hub also having another arm 112, which is acted upon by a cam 113 upon the periphery of the cam-disk 12. The clamp-plate 100 is thus actuated so as to clamp the needle-thread after the same has been out below the work-plate on the completion of a group of stitches. Hence the loose end of needle-thread is prevented from slipping or being drawn through the eye of the needle, but remains in proper position for the starting of the next group of stitches.

It will be observed on reference to Figs. 10 to 15 that the knife 83 comprises a finger 115, projecting forwardly beyond the cutting edge of the knife, said cutting edge being a downwardly-projecting blade 116 on the outer edge of the knife. The cutting-knife 84 is similarly formed and occupies a position between the knife 83 and the under side of the throatplate 81 of the machine.

The operation of the cutting-knives is as follows: Just as the needle ascends in forming the last stitch of the group and before the stop-motion devices act to arrest further movement of the machine the lever 82 is swung forward from the position shown in Fig. 6 to that shown in Figs. 10 and 13, so as to carry the forwardly-projecting finger 115 of the knife 83 into the loop of needle-thread 117 and also behind the thread 118, running from the bobbin to the needle-hole in the throat-plate, the forward end of the knife 84 being also carried behind said thread 118, as shown in said Figs. 10 and 13. This movement of the knifelever is that effected by the cam 92, as before described, and completes the first stage of movement of the knife-lever. When the machine is stopped, by shifting the driving-belt and bringing the bolt 39 into contact with the shoulder 42 of the cam 41 the movement imparted to the stop-arm 35 is transmitted to the knife-lever, so as to carry the latter quickly forward from the position shown in Fig. 10 to that shown in Fig. 12, from which position it is immediately drawn back to the position of Fig. 6 by the action of the spring 120. This quick forward movement constitutes the second stage of movement of the knife-lever, and its first effect is to sever the loop of needie-thread, which has meantime been drawn tightly around the finger 15 of the knife 83 by the rise of the needle, such severing being effected by the cutting edge 116 of said knife 83, as shown in Figs. 11 and 14. This operation, however, does not sever the bobbin-thread, for the reason that the latter extends downwardly from the knife 83 to the center of the bobbin, so as to be out of range of the cutting edge 116 of said knife 83; but as the forward movement of the knife-lever continues the cutting edge of the knife 84 severs the shuttle-thread at a point close to the needle-hole of the throat-plate, as shown in Figs. 12 and 15, so as to leave a comparatively longend of bobbin-thread extending from the bobbin up to and around the shank of the knife 83 and thence to the needle-hole, so that there will be ample length of such bobbin-thread to be caught by the first loop of needle-thread in commencing to form a new group of stitches.

The double-knife construction which I have just described is not essential to the proper carrying out of myinvention. For instance, the knife 83 may have two cutting edges 116 and 116" formed thereon, as shown in Fig. 16,

one cutting edge projecting downwardly to cut the loop of needle-thread and the other following the first and projecting upwardly, so as to cut the under thread, or the knife may be sharpened at the back, as shown at 116 in Fig. 17, in order to cut the under thread, or a sliding knife 12l--such, for instance, as shown in Figs. 18 and 19-may be employed to simultaneously cut the under thread and the loop of needle-thread just as the latter is approaching the needle-hole in the throat-plate, after the needle has risen above the same. Some of the features of my invention are also applicable to machines in which only the needle-thread is out, as in the former patented machine.

Having thus described my invention, I claim and desire to secure by Letters Patent- 1. The combination of the sewing mechanism of the machine, with a knife for cutting the loop of needle-thread after the formation -of a group of stitches, and mechanism for operating said knife by a two-stage movement,

said mechanism having as elements a cam and intervening devices for imparting the first stage of the movement to the knife, and a stop for preventing the knife from exceeding this first stage of movement, substantially as specified.

2. The combination of the sewing mechanism of the machine, with a knife for cutting the loop of needle-thread after the formation of a group of stitches, and mechanism for operating said knife, said mechanism comprising a cam and intervening devices for imparting the first stage of movement to the knife, a movable arm for arresting the movement of the driving-shaft of the machine, and means for transmitting the movement of said arm to the knife-operating devices so as to impart the second stage of movement to the knife, substantially as specified.

'3. The combination of the sewing mechanism of the machine, with a knife for cutting the loop of needle-thread after the formation of a group of stitches, and mechanism for operating said knife, said mechanism comprising a cam and intervening devices for imparting the first stage of movement to the knife, a stop for arresting the parts in the position to which they have been adjusted by said cam, a movable arm for arresting the movement of the driving-shaft of the machine, means for transmitting the movement of said arm to the knife-operating devices so as to impart the second stage of movement to the knife, and provision for releasing the stop, before such second movement, substantially as specified.

4E. The combination of the sewing mechanism of the machine, a knife for cutting the loop of needle-thread on the completion of a group of stitches, and mechanism for imparting movement to said knife, said mechanism having as elements a rock-shaft with two arms, one of which carries a trip-lever adapted to restrict its movement in one direction, and a cam-disk having a cam for acting upon one arm of the rock-shaft to impart movement thereto, and another cam for tripping said stop-lever in order to permit further backward movement of the shaft, substantially as specified.

5. The combination of the sewing mechanism of the machine, the movable stop-arm which receives the impact of a moving part of the machine in stopping the same, aworkholding clamp and means whereby the movement of the stop-arm is transmitted to the movable jaw of said work-holding clamp so as to open the same, substantially as specified.

6. The combination of the sewing mechanism of the machine, the movable stop-arm which receives the impact of a moving part of the machine in stopping the same, a workholding clamp, means whereby the movement of the stop-arm is transmitted to the movable jaw of said work-holding clamp so as to open the same, and a lock for retaining it in the opened position, substantially as specified.

7. The combination of the sewing mechanism of the machine, a knife for cutting the loop of needle-thread after the completion of a group of stitches, the work-holding clamp, mechanism for operating the cutting-knife by a two-stage movement, the second stage being due to a movable stop-lever, means for transmitting the movement of said stop-lever to the work-holding clamp so as to release the work, and locking devices for both the knifeoperating mechanism and the clamp-releasing devices, whereby the movement of the knife is arrested after it has received the first stage of its movement, and the work-holding clamp is held in the opened position until released, substantially as specified.

S. The combination of the driving-shaft of the sewing-machine, a movable stop which receives the impact of a moving part of the machine and arrests its forward movement when a group of stitches has been completed, and an automatic catch independent of said stop for preventing backward movement of the driving-shaft after its forward motion has been arrested, substantially as specified.

9. The combination of the sewing mechanism of the machine, a needle-thread cutter, a needle-thread clamp mounted upon the needle-bar, and mechanism whereby said clamp is caused to confine and release the needlethread, substantially as specified.

10. The combination of a sewing-machine having sewing mechanism for forming, in the work, a group of stitches with a two-thread lock-stitch, and cutting mechanism arranged and operated on one side of the work for automatically severing both the threads substantially at the stitching-point upon the completion of the group of stitches, substantially as specified.

11. The combination of a sewing-machine having sewing mechanism for formingagroup of stitches with double-thread lock-stitch, with an arm having knives, one for cutting the loop of needle-thread and the other for cutting the under thread after formation of the group of stitches has been completed, and means for operating said knives, substantially as specified.

12. The combination of a sewing-machine having sewing mechanism for producing a group of stitches with a double-thread lockstitch, with knives for automatically severing both threads after the completion of the group of stitches, and means for operating said knives, the knife for severing the under thread following the knife for severing the needle-thread in its action, substantially as specified.

13. The combination of a sewing-machine having sewing mechanism for producing a group of stitches with a double-thread lockstitch,and knives,one for severing the needle thread and the other for severing the under thread after the completion of the group of stitches,and means for operating said knives, said under-thread-severing knife occupying a position between the needle-thread-severing knife and the under side of the throatplate of the machine, substantially as specified.

14. The combination with a sewing-machine having sewing mechanism for producing, in the work, a group of stitches, of a cutting mechanism comprising a thread-cutting knife having a forwardly-projecting finger and, in the rear of the same, a cutting edge consisting of a blade projecting in a different plane from the body of the knife, substantially as specified.

15. In a sewing-machine, stitch-forming devices, comprising upper-thread mechanism and under-thread mechanism, and autothread below the work.

18. A sewing-machine, comprising twothread stitch-forming devices, a cutting device located below the work and having two cutting edges, one for the upper thread and the other for the lower thread, and means for operating said cutter.

19. In combination with a two-thread sewing-machine, a cutter and automatic means to cause it to sever the under thread below the work immediately upon the completion of a stitching operation.

20. In combination with a two-thread sewing-machine, a device located below the workplate for cutting the upper and under threads, means for operating said device, and means for locking said device in an inoperative position.

21. In combination with a two-thread sewing-machine, a device located below the work for cutting the under and the upper threads, means for intermittingly operating said cutting device, and means for intermittingly locking said device in an inoperative position.

22. In a sewingmachine, the combination with stitch-forming devices comprising an upper-thread mechanism and an underthread mechanism, of a cutting device movably mounted on the machine, and means for actuating said cutting device to sever the under thread independently of the needlethread, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ROBERT XV. THOMSON.

Witnesses:

JAMES E. ODLIN, CHAS. S. WING. 

